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37 lines
1.0 KiB
TypeScript
37 lines
1.0 KiB
TypeScript
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
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// This module is browser compatible.
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/**
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* Produces a random number between the inclusive `lower` and `upper` bounds.
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*/
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function randomInteger(lower: number, upper: number): number {
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return lower + Math.floor(Math.random() * (upper - lower + 1));
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}
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/**
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* Returns a random element from the given array.
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*
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* @typeParam T The type of the elements in the array.
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* @typeParam O The type of the accumulator.
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*
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* @param array The array to sample from.
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*
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* @returns A random element from the given array, or `undefined` if the array
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* is empty.
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*
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* @example Basic usage
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* ```ts
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* import { sample } from "@std/collections/sample";
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* import { assertArrayIncludes } from "@std/assert";
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*
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* const numbers = [1, 2, 3, 4];
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* const random = sample(numbers);
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*
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* assertArrayIncludes(numbers, [random]);
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* ```
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*/
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export function sample<T>(array: readonly T[]): T | undefined {
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const length = array.length;
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return length ? array[randomInteger(0, length - 1)] : undefined;
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}
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